Interplanetary Control of High‐Latitude Thermospheric Winds: Results From HIWIND and Model Simulations

Abstract

The thermospheric winds at high latitudes are impacted by both the pressure gradient changes via Joule heating and the ionospheric convection through ion drag, which are both associated with the energy deposition from the magnetosphere. Therefore, the high-latitude thermospheric winds are important indicators of the dynamic coupling process of the magnetosphere-ionosphere-thermosphere system. Over the past decades, thermospheric winds have been observed by satellite instruments (

HIWIND Balloon and Antarctica Jang Bogo FPI High Latitude Conjugate Thermospheric Wind Observations and Simulations

“…Tan et al. (2022) was mainly focused on the day‐to‐day variability of the HIWIND data in comparison with TIEGCM simulations.…”

“…In general, the winds from high latitudes have a strong diurnal variation in both zonal and meridional winds, which is the manifestation of the prevailing anti‐sunward winds resulted from day/night pressure gradient and possible anti‐sunward ion convection. In the case of the June 2018 data, the geomagnetic activity is very low (Tan et al., 2022), so the driving force of the anti‐sunward winds are most likely from the pressure gradient.…”

“…Conjugate comparison can show how the ionosphere thermosphere interacts during different seasons under nearly the same solar and geomagnetic conditions. The NASA supported High attitude Interferometer WIND observation (HIWIND) balloon FPI made a 5-day flight from Kiruna to northern Canada in June 2018, which finally provided much needed daytime summer thermospheric winds (for example, Moe & Wu, 2014;Tan et al, 2022;Wu et al, 2012Wu et al, , 2019aWu et al, , 2019bZhang et al, 2016). The last 2 days of 2018 HIWIND was located at magnetic latitude about 75°, which was investigated by Wu et al (2019b) and Tan et al (2022).…”

“…The NASA supported High attitude Interferometer WIND observation (HIWIND) balloon FPI made a 5-day flight from Kiruna to northern Canada in June 2018, which finally provided much needed daytime summer thermospheric winds (for example, Moe & Wu, 2014;Tan et al, 2022;Wu et al, 2012Wu et al, , 2019aWu et al, , 2019bZhang et al, 2016). The last 2 days of 2018 HIWIND was located at magnetic latitude about 75°, which was investigated by Wu et al (2019b) and Tan et al (2022). In recent years, more FPIs have been deployed in the high latitudes (for example, Wu et al, 2016).…”

A Numerical Investigation on the Formation of the Stalling of the Cross‐Polar Jet in Midnight Thermospheric Winds

“…Thermospheric winds at high latitudes are driven primarily by the ion drag associated with momentum transfer from the convecting plasma, Coriolis force, and pressure gradients caused by nonuniform temperature distributions due to solar radiative heating, Joule heating, and auroral particle precipitation (Killeen & Roble, 1988; Meriwether et al., 1973; Richmond et al., 2003; Roble et al., 1982; Tan et al., 2022; Wang & Luhr, 2016; Zhang et al., 2023). Driven by solar radiation‐produced pressure gradient force and the ion drag force associated with the convection pattern (Dungey, 1961), one of the large‐scale structures of the polar thermospheric wind is the anti‐sunward flow across the pole in the midnight sector, which is referred to as the “cross‐polar jet” (Smith et al., 1988, 1998).…”